In general, surgical mallets are known which are guided on devices for the insertion and/or extraction of implants, in particular intramedullary nails. U.S. Pat. No. 5,476,467 and WO 80/00534 disclose a mallet having a cylindrical shape and a centered bore which follows the longitudinal axis and by means of which the mallet slides over the insertion or extraction device. Guidance of these mallets may be difficult since the surgeon can only exert force on the mallet by gripping the cylinder on its lateral surface by hand. Moreover, these mallets can be used only with a particular insertion device.
Improved surgical mallets, such as those disclosed in U.S. Pat. No. 5,913,860 and in DE 19860569, disclose mallets which have a cylindrical mallet head and a mallet shaft for facilitating guidance of the surgical mallet. The surgical mallet of U.S. Pat. No. 5,913,860 not only has a cylindrical bore but also has a recess so that the surgical mallet can be introduced after assembly of the insertion device. Thus, this surgical mallet is universally applicable and, consequently, can be used as a mallet for directly driving, for example, nails into tissue. However, the guidance of the mallet on the insertion device may be complicated. Due to the slotted design, the mallet head may not be securely held on the implantation device (e.g., a guide rod) and, upon moving the mallet, the mallet may slip off the guide rod. As a result, the precision of a procedure may be impaired and the danger of injury may increase for the surgeon and others.
Furthermore, in a mallet embodiment having a slotted design, the slot intersects the base or impact surface of the cylindrical mallet head (i.e., the surface which is used for striking/impacting). Use of the mallet is complicated since it is necessary to ensure that the nail head, the nail end or other instruments which are used for insertion are struck with the intact surface and not in the area where a slot intersects the base surface. Therefore, the lateral or side surface of mallets designed in this manner (i.e., with a slot intersecting the base) are usually used as the impacting surface to impact an instrument. However, when hammering with the side surface of the mallet, the mallet head tends to be springy upon impact.
U.S. Pat. No. 6,592,590 discloses a surgical mallet which has a guide channel for a guide rod. The guide channel is designed so that the mallet head is prevented from being removed from the guide rod in the lateral direction. The impact surface of the mallet head is interrupted, so that the mallet can be reliably used only in combination with a guide rod. The mallet head tends to slip downwards from the guide rod on slight canting of the head. This may happen quickly since movement of the mallet on the guide rod is contradictory to natural human movement when impacting an object vertically. It is more advantageous to move the mallet in a gentle arc. However, it is the arc movement which leads to the guide rod slipping out of the slot of the mallet head.
It is desirable to have an impacting device, which provides the device for insertion and/or extraction of the implant (e.g., a guide rod), with guidance. Moreover it is desirable to have a impacting device, which may be attached to a guide rod after attaching the guide rod to an implant, is reliable for use in striking an implant and can be used universally with different types of guide rods and/or implants.